Field of the Invention
The present invention relates to an image reading device and an image forming system.
Description of the Related Art
Conventionally, an image reading device for color measurement of sheets of paper has been proposed, as is disclosed, for example, in JP 2007-153580 A, in which the heights of conveying rollers are changed according to the thickness of the sheet of paper to read the sheet of paper at an optimum depth of focus regardless of the thickness of the sheet of paper.
However, although in the prior art described in JP 2007-153580 A, variation in the height direction of a sheet of paper can be suppressed when the sheet of paper enters the conveying rollers, variation in the angular orientation of a sheet of paper cannot be suppressed when the sheet of paper enters the conveying rollers. Specifically, once the sheet of paper enters the conveying rollers, the sheet of paper shifts along the direction of rotation of the conveying rollers and the sheet of paper cannot be read at the optimum depth of focus.
Thus, in the prior art, the variation in the angular orientation of the sheet of paper cannot be suppressed, so that it is unable to keep the distance between a colorimeter and the sheet of paper constant and to improve color measurement accuracy.